Hi monks,

Nowadays, I am trying to develop a module which adds the following capability to a number storing scalar: In numeric context the scalar returns the number, and in string context it returns the stringified version of the number - in other words the name of the number.

The typical usage I plan is as follows; 

use warnings;
use strict;

use Test::More tests => 6;

use Attribute::StringifiableInteger;

my $integer : StringifiableInteger = 1;

ok($integer == 1);
is($integer, 'one');
is(sprintf("%d",$integer), 1);
is(sprintf("%s",$integer), 'one');

$integer = 3;

$integer += 1;
is($integer, 'four');

$integer++;
is($integer, 'five');

[download]
My problem begins with the last two lines of the example above; the increment operator is not overloaded as I expected.
The relevant part of the module code is as follows; 
use warnings;
use strict;

package StringifiableInteger;

use Carp;

use overload
    '""'  => \&_to_string,
    '0+'  => \&_get,
    '++'  => sub {
        my ($self) = @_;

        $$self += 1;

        return 'looks like the return value is not used.';
    },
    fallback => 1,
;

my $regex_integer = qr{
    ^
    -?
    \d+
    $
}x;

sub new {
    my ($class) = @_;

    my $integer;

    bless \$integer, $class;
}

sub set {
    my ($self, $value) = @_;

    croak "invalid integer value ($value)" unless $value =~ $regex_int
+eger;

    $$self = $value;
}

my @stringified = qw/zero one two three four five six seven eight nine
+ ten/;

sub _to_string {
    my ($self) = @_;

    return $stringified[$$self];
}

sub _get {
    my ($self) = @_;

    return $$self;
}


package TieStringifiableInteger;

sub TIESCALAR {
    my ($class) = @_;

    my $integer = StringifiableInteger->new;

    bless \$integer, $class;
}

sub STORE {
    my ($self, $value) = @_;

    $$self->set($value);
}

sub FETCH {
    my ($self) = @_;

    return $$self;
}

package AttributeStringifiableInteger;

use Attribute::Handlers;

sub UNIVERSAL::StringifiableInteger : ATTR(SCALAR) {
    my ($referent) = @_[2..2];

    tie $$referent, 'TieStringifiableInteger';
}

1;

[download]
I wonder whether there is a way to overload the ++ operator or not.
I also have another question;
What is your opinion on such a module? Is it worth uploading to CPAN?
A note; I am designing to module to add stringification for different languages. Like; 
use Attribute::StringifiableInteger lang => 'tr';

[download]
or, 
my $integer : StringifiableInteger('tr');

[download]

Thanks in advance,
Oguz

---------------------------------
life is ... $mutation = sub { $_[0] =~ s/(.)/rand()<0.1?1-$1:$1/ge };

In reply to Cannot overload ++ when the object is accessed via Attribute -> Tie -> Class by mayaTheCat

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